The US presidential transition was thrown into tumult on Monday, with Donald Trump blocking government co-operation with Joe Biden’s team and Attorney General William Barr authorising the Justice Department to investigate allegations of electoral fraud.

Some Republicans, including Senate majority leader Mitch McConnell, rallied behind Mr Trump’s efforts to fight the election results.

Few in the party acknowledged Joe Biden’s victory, or condemned Mr Trump’s other controversial move on Monday – his firing of Defence Secretary Mark Esper.

The developments cast doubt on whether the nation would witness the same kind of smooth transition of power that has long anchored its democracy.

The Electoral College is scheduled to formally confirm Mr Biden’s victory on December 14 and the Democrat will be sworn into office in late January.

On Monday, Mr Barr authorised the Justice Department to investigate “substantial” allegations of voter irregularities and election fraud, though no widespread instances of that type of trouble exist. In fact, election officials from both political parties have publicly stated that voting went well. International observers also confirmed there were no serious irregularities.

Biden campaign lawyer Bob Bauer said Mr Barr’s memorandum authorising investigations “will only fuel the ‘specious, speculative, fanciful or far-fetched claims’ he professes to guard against”.

Mr Biden pressed forward with plans to build his administration, assembling a team of experts to face the surging pandemic. But the federal agency that needs to greenlight the beginnings of the transition of power held off on taking that step. And the White House moved to crack down on those not deemed sufficiently loyal as Mr Trump continued to refuse to concede the race.

Mr Trump remained out of sight at the White House, with conversations ongoing about how the defeated president would spend the coming days and weeks as he challenged the people’s verdict.

The former reality TV star is not expected to formally concede but is likely to grudgingly vacate the White House at the end of his term, according to several people around him.

Also being discussed is the possibility of more campaign-style rallies as Mr Trump tries to keep his supporters fired up despite his defeat. It was possible they would feature his family and prominent supporters, but not the president himself.

The removal of Mr Esper, the Pentagon chief, was expected by some aides to be the first of several firings by Mr Trump. Others believed to now be vulnerable include FBI Director Christopher Wray, CIA head Gina Haspel and infectious disease expert Dr Anthony Fauci.

The president was given cover to keep fighting by Mr McConnell, seen by many in the GOP as the person who may eventually need to nudge Mr Trump to the exit.

“We have the system in place to consider concerns and President Trump is 100% within his rights to look into allegations of irregularities and weigh his legal options,” Mr McConnell said.

Senate Democratic leader Chuck Schumer countered that the Republicans’ refusal to accept the election results was “extremely dangerous, extremely poisonous to our democracy”.

Adding to the sense of uncertainty, the General Services Administration (GSA) held off on formally beginning the transition, preventing Mr Biden’s teams from gaining access to federal agencies.

A GSA spokesman said late on Monday an “ascertainment” on the winner of the election had not yet been made. Citing the agency’s response to the extended 2000 electoral recount, it signalled that it may not do so until Mr Trump concedes or the Electoral College meets next month.

On a call with reporters on Monday night, a transition official said the Biden team believed it was time for the GSA administrator to ascertain Mr Biden is president-elect. The official, who spoke on condition of anonymity, said legal action was “certainly a possibility” if that did not, though there are also other options being considered.

Across the government, there were signs of a slowdown.

White House officials and Trump political appointees informed career government staffers they were not to begin acting on transition planning until the GSA approved it, according to officials familiar with the matter.

But some elements of the federal government were mobilising to prepare for Biden to assume power. The US Secret Service and Federal Aviation Administration extended a flight restriction over Mr Biden’s Delaware home through Inauguration Day. Also, Mr Biden’s security detail has been bolstered with agents from the Presidential Protective Division.

Legal challenges already have been dismissed in battleground states like Georgia and Wisconsin. And Mr Trump’s legal efforts were dealt another blow Monday when campaign adviser David Bossie, tasked with leading the effort, tested positive for the coronavirus.

Mr Bossie had been at the indoor White House election night party now being perceived as a possible super-spreader event after other attendees — including chief of staff Mark Meadows, Secretary of Housing and Urban Development Ben Carson and other aides — contracted the virus.

Mr Trump’s public schedule hasn’t included an intelligence briefing since Oct. 1. The White House hasn’t provided a “readout” of any call between the president and a foreign leader in weeks. He hasn’t met with members of the White House coronavirus task force in months. He also offered no public comment on Tropical Storm Eta lashing the Florida Keys.